ACA is an unexpensive taste of a Nelson Pass amp. I have only heard a few, but i would strongly suspect that bigger 1st wat tclones would be better (i only have ACA & SIT-3 as refs).
dave
dave
Hi Alan
IF you‘re going the ACA path, and intend to mod & extend it, (and don‘t build the chassis yourself), I’d recommend getting a mini dissipate a bit bigger then the original one. ACA has plenty of space in the original, but with a power-supply and pot it gets a bit dense. (there‘s a build with the brick stuffed inside, but—phew)
Just my 2c
David
what attracted me to the ACA is the single gain stage, CCS load, (you can replace with a choke) very simple design....
Got my ACA regulated linear power supplies up and running this week. Sellarz Power supply boards with Toroidy fully shielded premium grade Audio transformer supported over the top of the PCB and all in Mini Dissipante case to match the ACA kit.
It's worth noting the transformer itself and ACA still get pretty warm even with all those fins. I have a spare power supply board now that's begging to be matched with a smaller Toroidy to power the Korg Nutube pre - amp. At the moment the ACA are stock of the shelf except for solid core gold plated wiring. May be some Audio note caps and resistors are in order at some point but I have a Pearl 2 to build first.
NB Identical ACA and power supply (bridged mono) behind each speaker.
It's worth noting the transformer itself and ACA still get pretty warm even with all those fins. I have a spare power supply board now that's begging to be matched with a smaller Toroidy to power the Korg Nutube pre - amp. At the moment the ACA are stock of the shelf except for solid core gold plated wiring. May be some Audio note caps and resistors are in order at some point but I have a Pearl 2 to build first.
NB Identical ACA and power supply (bridged mono) behind each speaker.
Last edited:
The room is large enough...
Actually it's kitchen, dining and living room in one open space of 80 m² (860 ft²).
Pass DIY Addict
Joined 2000
Paid Member
Steve - awesome looking set! I like the exposed shiny transformer top!
Dennis - great to see another ACA "on the cheap" ! I've built lots of these little guys and each one hasn't cost me more than about $60-70 using surplus sinks and a few pieces of wood. The biggest cost is the parts followed by a pair of boards, all of the rest has been surplus or parts laying around that I've scrounged over the years.
Dennis - great to see another ACA "on the cheap" ! I've built lots of these little guys and each one hasn't cost me more than about $60-70 using surplus sinks and a few pieces of wood. The biggest cost is the parts followed by a pair of boards, all of the rest has been surplus or parts laying around that I've scrounged over the years.
Pass DIY Addict
Joined 2000
Paid Member
I'm thinking I've made six ACAs over the years. Have boards for a few more that I haven't built yet...
I've built two original stereo kits, with modifications
plus two complete amps with linear PSUs in the Hafler DH-220 chassis
8 channels total
plus two complete amps with linear PSUs in the Hafler DH-220 chassis
8 channels total
Pass DIY Addict
Joined 2000
Paid Member